Gyroscope is an inertial sensing element and mainly measures angular velocity of a rotation by law of inertia. Traditional gyroscopes work by utilizing conservation law of angular momentum and are mainly applied for navigation in the fields of military, aeronautics and sailing. However, traditional gyroscopes have problems of with complicated structure and been fast wear and tear such that traditional gyroscopes have short usage of life, expensive price and heavy weight.
By developments of consumer industry, the demands of gyroscopes with light weight, cheap price and long usage of life increase in the fields of inertial navigation, automobile, robot, medical engineering, consumer electronics and electronic entertainments. Due to recent evolvement of semiconductor technology, Microelectromechanical (MEMS) process technology combining semiconductor process, mechanical and electronic technology makes more and more progress. Therefore, a micro gyroscope sensor with light weight and cheap price can be manufactured by MEMS technology.
In gyroscope sensors, vibrating sensor for sensing rotation is main stream and is disclosed in quite many prior arts. For example, the technique disclosed in U.S. Pat. No. 4,381,672 senses rotation by using a single cantilever beam structure. However, the center of mass of the cantilever structure will change continuously due to vibration of the cantilever beam, so that noise will occurs to disturb the measured results. Therefore, U.S. Pat. Nos. 5,445,025 and 6,201,341 utilize symmetrical vibrating structures for overcoming the drawback of changing center of mass. However, the structures disclosed in the above-mentioned two patents can not be minified by MEMS process technology even if they can solve the problem of changing center of mass due to asymmetric structure.
In view of the above-mentioned problems, an improved rotation sensing apparatus and method for manufacturing the same is required to solve the defects of the prior arts.